Osteopontin expression is a valuable marker for prediction of short-term recurrence in WHO grade I benign meningiomas

Prediction of recurrence remains a challenge in histopathological benign/grade I tumors. Osteopontin (OPN) plays important roles in tumorigenesis, invasion, and metastasis of several human cancers. In this study, we investigated OPN protein expression by evaluating the differences between recurrent and non-recurrent histologically benign meningiomas. Thirty-two patients were enrolled, and 23 benign non-recurrent meningiomas and 9 benign recurrent meningiomas were followed for a mean of 34 months after complete surgical resection (Simpson grades I and II). Cytoplasmic OPN staining was evaluated by means of immunohistochemistry (IHC) score and by use of the Allred-8-unit system. We examined clinical biological data, their relationship with tumor recurrence, and the expression of OPN. Our results showed that meningioma recurrence correlated significantly with OPN IHC score (P = 0.001). An OPN Allred score between 0 and 3 was associated with a recurrence-free time of more than 25 months. In comparison, an OPN Allred score from 4 to 8 was indicative of a shorter average recurrence-free time. We concluded that OPN IHC score may play a role in prediction of the recurrence of the grade I meningiomas. Moreover, determination of the OPN Allred score is a reliable, quantitative tool for predicting recurrence-free time in benign meningioma patients.